Quick connect hydraulic and pneumatic couplings typically include a male portion in operable engagement with a female portion. The male and female portions may be interconnected to a hydraulic hose, tubing, piping, machinery or open apparatus that utilizes internal pressure. Since hydraulic hoses and interconnecting machinery often utilize high pressure fluids, safety and operational considerations are paramount since an inadvertent disconnection of the coupling may result in serious injury or system failure. Quick connect couplings are particularly desirable in locations that are not readily accessible since it often eliminates the need for engaging a threaded connection and the associated danger of cross threading.
It is also critical that quick connect couplings be designed for safe and reliable use. Obviously, one of the primary objectives is to provide a durable, leak-free connection. However, over time, increasing emphasis has been placed on safety. The quick connect characteristic of such couplings necessarily give rise to a greater risk of inadvertent and sudden disconnects, which may translate to catastrophic failure of the system or bodily injury. This is particularly evident in environments where use of such couplings is generally appealing. These include industrial or heavy machinery operations where installations of fluid connections are numerous, dense, and almost inaccessible. Unexpected impacts or continuous vibrational loads upon quick connect couplings during normal operations or maintenance may increase the likelihood of inadvertent disconnects. Further, inadvertent disconnects on pressurized systems can lead to damaged or broken machinery, destroyed premises, loss of mission, severe injuries and even death.
In general, the male portion of a quick connect coupling includes a hose insert portion and a ferrule that is attached to an open end of the hose. The ferrule is then compressed about the hose that is positioned around the hose insert causing it to be permanently affixed. Merely pressing a stem of the male portion into the female portion, or similarly configured port, subsequently completes a flow path for a liquid or gas, such as compressed air. Generally, the female portion, or port adapter, is threaded into place in a pre-assembly operation, or alternatively, it is machined directly into then associated fixture, machine, or equipment. Thus, it is easy to ensure that the port is properly sized to receive the male portion.
Quick connect couplings have numerous uses and applications in the home and in many industries, including aerospace, automotive, construction, farming, etc. Generally, where there is a need for continuous connection and subsequent disconnection of fluid or gas lines, or the location of the intended connection makes it difficult of impossible to access, such that a threaded interconnection would be infeasible, a quick connect is ideal.
Some quick connects are provided with a groove integrated into the male portion for the receipt of a locking device. Generally, the locking device is a snap ring that comprises a cylindrical member with an inner and outer diameter. The snap ring includes a gap such that it is capable of resilient deflection to form a ring of smaller or larger diameter. In some embodiments of the prior art, such as the QC series sold by Swagelok®, the snap ring is placed over a groove integrated into the outer diameter of the male portion. After insertion of the male portion into the female portion, a ring deflection mechanism or sleeve is forced over the snap ring, thereby deforming it into a groove located in the male portion to prevent disconnection. The sleeve is held in place over the snap ring by a spring mechanism. To disconnect the two components, the sleeve is pulled towards the spring, thus releasing the compressed snap ring from the groove and allowing the two portions to be disengaged.
Another example of a quick connect coupling may be found in U.S. Pat. No. 6,637,781 to Seymour, (“Seymour”) which is incorporated by reference in its entirety herein. Seymour teaches a quick connect system that utilizes a male portion and a female portion that selectively interconnect. The male portion is adapted to receive a sealing device, such as an o-ring and a resiliently deflectable snap ring. Upon insertion of the male portion into the female portion, the snap ring will radially deflect and engage grooves in both portions to lock the system together. A spacer is positioned between bearing surfaces on each of the portions to prevent movement of the male portion with respect to the female portion. To disconnect the coupling, a user removes the spacer from the coupling, thus allowing the male portion to be inserted further into the female portion, and repositioning the snap ring on the stem of the male portion. Once the snap ring reaches a certain point on the stem, it deflects to its nominal shape, thus allowing the male portion to be removed from the female portion. However, the apparatus described in Seymour is still subject to inadvertent release once the spacer is removed if the male stem is inadvertently pushed inwardly into the female coupling.
Thus, there is a long felt need for a quick connect coupling that utilizes a mechanical lock that is selectively unlocked by a release mechanism. Further, there is a need to ensure that the release mechanism is ineffective unless pressure in the coupling is reduced, an obstruction is removed, a cam is rotated, or a release assembly is actuated. That is, it is desirable that a second mechanical or pneumatic event must be performed or occur before the primary release mechanism can be actuated and the coupling disconnected.